-- hack: set the hyperlink color so that caller can draw the text of the
  -- hyperlink in the same color
  App.color(Hyperlink_decoration_color)
  love.graphics.line(x,y+Editor_state.line_height, x+button_params.w,y+Editor_state.line_height)

  App.screen.check(y, 'mn', 'screen:3')
end
function test_pagedown_never_moves_up()

  local final_screen_line_starting_pos = startpos  -- track value to return
  Text.populate_link_offsets(State, line_index)
  assert(#line_cache.screen_line_starting_pos >= 1)
  for i=1,#line_cache.screen_line_starting_pos do
    local pos = line_cache.screen_line_starting_pos[i]
      -- render fragment
        Text.draw_highlight(State, line, State.left,y, pos, lo,hi)
      select_color(f)
      App.screen.print(f, State.left,y)
      if not hide_cursor and line_index == State.cursor1.line then
        if pos <= State.cursor1.pos and pos + frag_len >= State.cursor1.pos then
              local lo_px = Text.draw_highlight(State, line, State.left,y, pos, State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term))
              love.graphics.print(State.search_term, State.left+lo_px,y)
            Text.draw_cursor(State, State.left+Text.x(f, State.cursor1.pos-pos+1), y)
      y = y + State.line_height
      if y >= App.screen.height then
        break
      end
  return y, final_screen_line_starting_pos
end
function Text.screen_line(line, line_cache, i)
  local pos = line_cache.screen_line_starting_pos[i]
  local offset = Text.offset(line.data, pos)
  if i >= #line_cache.screen_line_starting_pos then
    return line.data:sub(offset)
  local endpos = line_cache.screen_line_starting_pos[i+1]-1
  local end_offset = Text.offset(line.data, endpos)
  return line.data:sub(offset, end_offset)
  local x = 0
  -- try to wrap at word boundaries
  for frag in line.data:gmatch('%S*%s*') do
    local frag_width = App.width(frag)
--?     print('-- frag:', frag, pos, x, frag_width, State.width)
    while x + frag_width > State.width do
--?       print('frag:', frag, pos, x, frag_width, State.width)
      if x < 0.8 * State.width then
        -- long word; chop it at some letter
        -- We're not going to reimplement TeX here.
        local bpos = Text.nearest_pos_less_than(frag, State.width - x)
        -- everything works if bpos == 0, but is a little inefficient
        pos = pos + bpos
        local boffset = Text.offset(frag, bpos+1)  -- byte _after_ bpos
        frag = string.sub(frag, boffset)
--?         if bpos > 0 then
--?           print('after chop:', frag)
--?         end
        frag_width = App.width(frag)
      end
--?       print('screen line:', pos)
      x = 0  -- new screen line
    pos = pos + utf8.len(frag)
function Text.populate_link_offsets(State, line_index)
  if line_cache.link_offsets then
  line_cache.link_offsets = {}
  local pos = 1
  local s, e = 1, 0
  while s <= #line.data do
    s, e = line.data:find('%[%[%S+%]%]', s)
    if s == nil then break end
    local word = line.data:sub(s+2, e-2)  -- strip out surrounding '[[..]]'
--?     print('wikiword:', s, e, word)
    table.insert(line_cache.link_offsets, {s, e, word})
    s = e + 1
  end
end
-- Intersect the filename between byte offsets s,e with the bounds of screen line i.
-- Return the left/right pixel coordinates of of the intersection,
-- or nil if it doesn't intersect with screen line i.
function Text.clip_wikiword_with_screen_line(line, line_cache, i, s, e)
  local spos = line_cache.screen_line_starting_pos[i]
  local soff = Text.offset(line.data, spos)
  if e < soff then
    return
  end
  local eoff
  if i < #line_cache.screen_line_starting_pos then
    local epos = line_cache.screen_line_starting_pos[i+1]
    eoff = Text.offset(line.data, epos)
    if s > eoff then
      return
  end
  local loff = math.max(s, soff)
  local hoff
  if eoff then
    hoff = math.min(e, eoff)
  else
    hoff = e
--?   print(s, e, soff, eoff, loff, hoff)
  return App.width(line.data:sub(1, loff-1)), App.width(line.data:sub(1, hoff))
  State.line_cache[line_index].link_offsets = nil
end
function trim(s)
  return s:gsub('^%s+', ''):gsub('%s+$', '')
end
function ltrim(s)
  return s:gsub('^%s+', '')
end
function rtrim(s)
  return s:gsub('%s+$', '')
  edit.draw(State)
  return State.cursor_y == nil
  -- this approach is cheaper and almost works, except on the final screen
  -- where file ends above bottom of screen
--?   local botpos = Text.pos_at_start_of_screen_line(State, State.cursor1)
--?   local botline1 = {line=State.cursor1.line, pos=botpos}
--?   return Text.lt1(State.screen_bottom1, botline1)
end
end
  end
    end
  -- try to wrap at word boundaries
    return
  end
  local line = State.lines[line_index]
  end
end
    end
    x = x + frag_width
      table.insert(line_cache.screen_line_starting_pos, pos)
  local pos = 1
end
function Text.draw_cursor(State, x, y)
  -- blink every 0.5s
  if math.floor(Cursor_time*2)%2 == 0 then
    App.color(Cursor_color)
    love.graphics.rectangle('fill', x,y, 3,State.line_height)
  end
  State.cursor_x = x
  State.cursor_y = y+State.line_height
end
function Text.populate_screen_line_starting_pos(State, line_index)
  local line = State.lines[line_index]
  end
    end
          end
        end
      end
            end
          elseif Focus == 'edit' then
              App.color(Text_color)
          if State.search_term then
            if State.lines[State.cursor1.line].data:sub(State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term)-1) == State.search_term then
      -- render cursor if necessary
      end
      if State.selection1.line then
        local lo, hi = Text.clip_selection(State, line_index, pos, pos+frag_len)
      final_screen_line_starting_pos = pos
      local f = Text.screen_line(line, line_cache, i)
--?       print('text.draw:', f, 'at', line_index,pos, 'after', x,y)
      local frag_len = utf8.len(f)
      -- render any link decorations
      for _,link_offsets in ipairs(line_cache.link_offsets) do
        local s,e,filename = unpack(link_offsets)
        local lo, hi = Text.clip_wikiword_with_screen_line(line, line_cache, i, s, e)
        if lo then
          button(State, 'link', {x=State.left+lo, y=y, w=hi-lo, h=State.line_height, color={1,1,1},
            icon = icon.hyperlink_decoration,
            onpress1 = function()
                         if file_exists(filename) then
                           source.switch_to_file(filename)
                         end
                       end,
          })
        end
    if pos < startpos then
      -- render nothing
  initialize_color()
  Text.populate_screen_line_starting_pos(State, line_index)
-- return y for the next line, and position of start of final screen line drawn
function Text.draw(State, line_index, y, startpos, hide_cursor)

          Text.draw(State, line_index, y, --[[startpos]] 1)
          State.left,State.right = old_left,old_right
        else
          height = log_render[line.data.name](line.data, xleft, y, xright-xleft)
        end
      end
      if App.mouse_x() > Log_browser_state.left and line_index == mouse_line_index then
        App.color(Cursor_line_background_color)
        love.graphics.rectangle('fill', xleft,y, xright-xleft, height)
      end
      y = y + height
    end
  end
end
function render_stack_left_margin(State, line_index, line, y)
  if line.section_stack == nil then
    -- assertion message
    for k,v in pairs(line) do
      print(k)
    end
  end
  App.color(Section_border_color)
  for i=1,#line.section_stack do
    local x = State.left + (i-1)*Section_border_padding_horizontal
    love.graphics.line(x,y, x,y+log_browser.height(State, line_index))
    if y < 30 then
      love.graphics.print(line.section_stack[i].name, x+State.font_height+5, y+5, --[[vertically]] math.pi/2)
    end
    if y > App.screen.height-log_browser.height(State, line_index) then